A rapid and sensitive method for acetate determination in human plasma and in hemodialysis baths (dialysates) is going to become necessary owing to the extensive using of sodium acetate solution in hemodialysis. The gas chromatographic method reported here allows, in about 35 minutes, the precise and reproducible measurement of acetate concentrations ranging from 0.2 to 20 mmol/1. This method can be used to investigate the kinetics of acetate concentration variations in the blood of patients undergoing hemodialysis with sodium acetate solution and to evaluate the amount of acetate absorbed during this treatment.